Methods of performing electron-beam evaporation are well known, and the use of crucible inserts in seeking to optimize the efficiency of such processes is also well known. Electron-beam evaporation is used to apply a coating of a deposition material to a substrate. The deposition material often is comprised of metal or intermetallic compounds, such as gold, silver, copper, or aluminum. Generally, the deposition material is placed in a reservoir or evaporator pot having an opening or mouth, and the substrate to be coated is placed adjacent the mouth. A beam of electrons is directed into the reservoir, causing the deposition material to evaporate out of the mouth and adhere to the substrate.
When a crucible is used, the deposition material is placed in the crucible, the crucible is inserted into the evaporator pot, and the electron beams are directed into the crucible. When a crucible is properly selected, it can reduce the time it takes for the deposition material to evaporate onto the substrate. Also, if one wants to change the deposition material being evaporated, the crucible can simplify this process, because one can simply change the crucible (and evaporation materials) without having to change or clean the entire evaporator pot. Therefore, crucibles have proved advantageous to the electron-beam evaporation process.
However, when prior art crucibles are used, deposition material often spatters onto the evaporator pot or the lining of the evaporator. The spattered material can result in the buildup of residue on the evaporator pot that requires cleaning or chipping from time to time. This cleaning process requires a downtime during which the evaporator cannot be used, thereby reducing its efficiency. This spattering and excessive coating is more fully explained, below, with reference to the drawings and more particularly FIGS. 1A and 1B.
The present invention is, therefore, addressed to providing an improved crucible that eliminates or reduces the spattering of deposition material during the evaporation process, as well as an improved method of performing electron-beam evaporation that results in reduced spattering. The invention provides advantages in that it eliminates or reduces the need to clean the evaporator pot, minimizes waste of the deposition materials, improves the efficiency of the system, and also provides a crucible that is easier for a user to handle. Further advantages may be revealed to one skilled in the art following from the description detailed below.